The present invention relates to toilets, and more particularly to valves controlling the outflow of waste from a toilet bowl to a toilet trap.
Although flushing type toilets aid in the sanitary disposal of human excrement, their level of water usage is of concern. A typical toilet includes a valve upstream of the toilet bowl, such as at the bottom of a water storage tank. When the toilet is flushed, the valve in such a water tank opens, and the tank water is able to flush into the toilet bowl.
However, with these conventional toilets, there is typically a delay between the beginning of the flushing cycle and the time that most of the crude waste has been removed from the bowl. Thus, there can be an undesirably large amount of flushing water required to just move the main waste out of the bowl, and a further amount is needed to provide the final rinse.
One approach for reducing this level of water usage is to provide an outlet valve immediately downstream of the toilet bowl outlet that is configured such that when it is opened most of the waste in the bowl can drop out of the bowl regardless of any new flush water entering the bowl. An example of this approach is depicted in U.S. Pat. No. 279,048.
However, such valves sometimes result in clogging, maintenance or wear problems. Also, they may be expensive to produce or install, or be unreliable over prolonged use, particularly when closure is directly into the face of the bowl discharge outlet flow.
U.S. Pat. No. 5,345,618 teaches a trap valve connected to a toilet bowl discharge outlet where a sphere segment gate is caused to rotate on an axis that is also the center of radius for the sphere. This provides a sliding closure of the discharge outlet. A problem with this design is that as the spherical gate rotates across the sealing element or gasket, the gate is continuously abrading the gasket, which wears the gasket and can lead to a loss of fluidic seal at the valve gate. Further, the bowl outlet which is closed by the gate, is positioned in a horizontal plane which causes the leading edge of the gate to start closing the orifice from an approximate 9 o'clock position to beyond a 3 o'clock position. This involves some movement during the closure against the gravity force of the bowl waste.
Other examples of trap valves and valves with sphere segment gates are disclosed in U.S. Pat. Nos. 289,495, 3,214,772, 3,599,248, 3,885,771, 3,926,407, 4,164,343, 6,212,700, 5,345,618, 6,332,229; as well as U.S. patent application 2005/0211942. However, notwithstanding these developments, a need still exists for improved toilet trap valve assemblies, particularly those which facilitate flushing with reduced amounts of water.